1. Field of the Invention
The present invention relates to an optical pick-up system, and more particularly to an automatic camera. Still more specifically, the invention relates to means for detecting the relative motion of objects in an area to be photographed and for actuating a shutter according to the detection of such relative motion.
2. Description of the Prior Art
In the camera art it is well known that to obtain a properly exposed picture it is necessary to adjust the distance between the camera and an object to be photographed, as well as the aperture of the diaphragm and the shutter speed in due order. To facilitate the different adjustments modern cameras comprise automatic or coupled distance measuring equipment, as well as automatic light meters incorporated in the camera. Since only appropriate combinations of shutter speed, aperture of diaphragm, and sensitivity of film assure well-exposed pictures, these values have to be determined with respect to the brightness measured by a light meter.
Most modern high quality cameras, especially single-lens reflex cameras, comprise the afore-mentioned equipment as standard items. The main difference of such cameras is between the type of distance measuring equipment, e.g. double-image range finder or split-field range finder or combination range finder, and the light-meter type or system e.g. light meters of the internal or the external measuring type, comprising light-sensitive elements made of selenium or silicon, or being photo-conducting cells and the like. A further distinguishing characteristic is whether or not the light meter operates when the diaphragm is opened.
However, many users of modern cameras find it too complicated or inconvenient to be forced to adjust three different values manually, namely distance, shutter speed, and aperture of diaphragm, by turning setting rings before shooting a photograph.
To eliminate these objections and facilitate the handling of the cameras, improvements have been made recently which require the user to adjust only two values manually, namely distance and shutter speed or distance and diaphragm aperture. Thus, only the shutter speed or the diaphragm aperture, respectively, is the independent and manually adjustable value, whereas the diaphragm aperture or the shutter speed, respectively, is the automatically calculated and adjusted value.
Using these so-called semi-automatic cameras with an exposure system of the shutter speed-priority type or of the diaphragm aperture-priority type, most photographic problems can be satisfactorily solved, since most photographic shooting requires either certain exposure times to avoid movement blurs or certain diaphragm apertures to achieve a predetermined depth of focus.
Besides the semi-automatic cameras, so-called fully automatic cameras have also been developed which include a program ring comprising cams for controlling the adjustment of the shutter and the diaphragm. Through this means an exposure program is available which determines a special exposure combination as a function of the sensitivity of the film and of the light conditions. Under bad conditions of illumination, for instance, a relatively fast shutter speed and a relatively great diaphragm aperture are selected, since the emphasis of the program is upon the reduction of blurring rather than upon the achievement of a sufficient depth of focus. Only when the illumination conditions become better or even excellent, will the program allow a better depth of focus.
Some of the photographers consider it to be a disadvantage that these fully-automatic cameras do not afford them the opportunity to select the shutter speed or the diaphragm aperture manually, so as to achieve the best photographic results. Therefore, the fully-automatic system has not thus far been incorporated to a noticeable degree in high-quality cameras, despite the fact that the fully-automatic cameras using electronic control systems are very easy to handle (cf. German Pat. No. 2,353,924 and German Offenlegungsschrift Nos. 25 21 824, 25 34 656, 26 01 606).
It has also been proposed, however, to incorporate a more sophisticated control system in modern high quality cameras (cf. German Offenlegungsschrift No. 26 51 002). This proposal makes it possible to choose between a semi-automatic system having a shutter speed-priority and a semi-automatic system having a diaphragm aperture-priority.
This new system is conventional insofar as the only determining values are the sensitivity of the film and the brightness of the area to be photographed. Furthermore, it lacks the possibility of fully-automatic operation.